Source Edit

nimphea_field

Nim wrapper for Electro-Smith Daisy Field development board.

The Daisy Field is a large Eurorack-format module featuring:

16-key capacitive touch keyboard (2× 8-key rows)
8 potentiometers with LEDs
4 CV inputs (±5V)
2 CV outputs (0-5V via DAC)
2 gate inputs
1 gate output
OLED display (128×64, SPI)
26 RGB LEDs (16 keyboard, 8 knob, 2 switch)
2 tactile switches with LEDs
MIDI I/O (TRS jacks)
Audio I/O (Eurorack level)

Hardware Overview:

Based on Daisy Seed (STM32H750, 480MHz ARM Cortex-M7)
Eurorack format (42HP wide)
Perfect for keyboard synthesizers, sequencers, CV processors

Example - Keyboard and display:

import nimphea/boards/daisy_field

var field: DaisyField
field.init()

while true:
  field.processAllControls()
  
  # Check keyboard
  for key in 0..<16:
    if field.keyboardRisingEdge(key):
      # Key was just pressed
      field.led_driver.setLed(key, 1.0)
  
  field.display.fill(false)
  field.display.setCursor(0, 0)
  field.display.writeString("Hello Field!", Font_7x10, true)
  field.display.update()
  
  field.seed.delay(10)

Example - CV processing:

while true:
  field.processAnalogControls()
  
  let cv1 = field.getCvValue(CV_1)  # Read CV input
  let knob1 = field.getKnobValue(KNOB_1)
  
  let processed = cv1 * knob1  # Process CV
  
  # Output via DAC (0-4095 = 0-5V)
  let dacValue = (processed * 4095.0).uint16
  field.setCvOut1(dacValue)

Imports

nimphea, oled_display, gatein, switch, leddriver

Types

AnalogControl {.importcpp: "daisy::AnalogControl", header: "hid/ctrl.h".} = object

Analog control (knob/CV input) wrapper Source Edit

DaisyField {.importcpp: "daisy::DaisyField".} = object
  seed*: DaisySeed           ## Underlying Seed board
  display*: OledDisplay128x64Spi ## 128×64 OLED display (SPI)
  gate_out*: GPIO            ## Gate output pin
  gate_in*: GateIn           ## Gate input
  led_driver*: FieldLedDriver ## LED driver (2× PCA9685, daisy-chained) - v0.12.0 fix
  sw*: array[2, Switch]      ## 2 tactile switches
  knob*: array[8, AnalogControl] ## 8 potentiometers
  cv*: array[4, AnalogControl] ## 4 CV inputs
  midi*: MidiUartHandler     ## MIDI UART handler

Daisy Field board handle

Contains all hardware peripherals pre-configured for the Field platform.

Source Edit

FieldCV = enum
  CV_1 = 0,                 ## CV input 1 (±5V)
  CV_2 = 1,                 ## CV input 2 (±5V)
  CV_3 = 2,                 ## CV input 3 (±5V)
  CV_4 = 3                   ## CV input 4 (±5V)

CV input identifiers Source Edit

FieldKnob = enum
  KNOB_1 = 0, KNOB_2 = 1, KNOB_3 = 2, KNOB_4 = 3, KNOB_5 = 4, KNOB_6 = 5,
  KNOB_7 = 6, KNOB_8 = 7

Knob (potentiometer) identifiers Layout: Left to right on panel Source Edit

FieldLed = enum
  LED_KEY_B1 = 0, LED_KEY_B2 = 1, LED_KEY_B3 = 2, LED_KEY_B4 = 3,
  LED_KEY_B5 = 4, LED_KEY_B6 = 5, LED_KEY_B7 = 6, LED_KEY_B8 = 7,
  LED_KEY_A8 = 8, LED_KEY_A7 = 9, LED_KEY_A6 = 10, LED_KEY_A5 = 11,
  LED_KEY_A4 = 12, LED_KEY_A3 = 13, LED_KEY_A2 = 14, LED_KEY_A1 = 15, ## 8 knob LEDs (left to right)
  LED_KNOB_1 = 16, LED_KNOB_2 = 17, LED_KNOB_3 = 18, LED_KNOB_4 = 19,
  LED_KNOB_5 = 20, LED_KNOB_6 = 21, LED_KNOB_7 = 22, LED_KNOB_8 = 23, ## 2 switch LEDs
  LED_SW_1 = 24, LED_SW_2 = 25

LED identifiers (26 total) 16 keyboard LEDs (Row B then Row A, right to left) Source Edit

FieldSwitch = enum
  SW_1 = 0,                 ## Left switch
  SW_2 = 1                   ## Right switch

Tactile switch identifiers Source Edit

MidiUartHandler {.importcpp: "daisy::MidiHandler<daisy::MidiUartTransport>",
                  header: "hid/midi.h".} = object

MIDI UART handler Source Edit

MidiUartTransport {.importcpp: "daisy::MidiUartTransport", header: "hid/midi.h".} = object

MIDI UART transport Source Edit

Procs

proc audioBlockSize(this: var DaisyField): csize_t {. importcpp: "#.AudioBlockSize()", ...raises: [], tags: [], forbids: [].}: Get current audio block size Source Edit
proc audioCallbackRate(this: var DaisyField): cfloat {. importcpp: "#.AudioCallbackRate()", ...raises: [], tags: [], forbids: [].}: Get audio callback rate in Hz Source Edit
proc audioSampleRate(this: var DaisyField): cfloat {. importcpp: "#.AudioSampleRate()", ...raises: [], tags: [], forbids: [].}: Get current audio sample rate in Hz Source Edit
proc changeAudioCallback(field: var DaisyField; callback: AudioCallback) {. ...raises: [], tags: [], forbids: [].}: Change the audio callback while audio is running Source Edit
proc changeAudioCallback(field: var DaisyField; callback: InterleavingAudioCallback) {....raises: [], tags: [], forbids: [].}: Change the interleaved audio callback while audio is running Source Edit
proc delay(this: var DaisyField; milliseconds: int) {.inline, ...raises: [], tags: [], forbids: [].}: Delay execution (convenience wrapper) Source Edit
proc delayMs(this: var DaisyField; del: csize_t) {.importcpp: "#.DelayMs(#)", ...raises: [], tags: [], forbids: [].}: Delay execution for specified milliseconds

Parameters:

del - Delay time in milliseconds

Source Edit
proc getCv(this: var DaisyField; idx: csize_t): ptr AnalogControl {. importcpp: "#.GetCv(#)", ...raises: [], tags: [], forbids: [].}: Get pointer to CV input (AnalogControl) object

Parameters:

idx - CV input index (0-3)

Returns: Pointer to AnalogControl object
Source Edit
proc getCvValue(this: DaisyField; idx: csize_t): cfloat {. importcpp: "#.GetCvValue(#)", ...raises: [], tags: [], forbids: [].}: Read CV input value

Parameters:

idx - CV input index (0-3, or use FieldCV enum)

Returns: Voltage value (±5V range, scaled to 0.0-1.0)

Voltage mapping:

0.0 → -5V

0.5 → 0V

1.0 → +5V

Example:

let cv1Raw = field.getCvValue(CV_1.csize_t) let cv1Volts = (cv1Raw - 0.5) * 10.0 # Convert to ±5V
Source Edit
proc getKnob(this: var DaisyField; idx: csize_t): ptr AnalogControl {. importcpp: "#.GetKnob(#)", ...raises: [], tags: [], forbids: [].}: Get pointer to knob (AnalogControl) object

Parameters:

idx - Knob index (0-7)

Returns: Pointer to AnalogControl object
Source Edit
proc getKnobValue(this: DaisyField; idx: csize_t): cfloat {. importcpp: "#.GetKnobValue(#)", ...raises: [], tags: [], forbids: [].}: Read knob value

Parameters:

idx - Knob index (0-7, or use FieldKnob enum)

Returns: Normalized value from 0.0 to 1.0

Note: Call processAnalogControls() regularly for accurate readings.

Example:

let cutoff = field.getKnobValue(KNOB_1.csize_t) let resonance = field.getKnobValue(KNOB_2.csize_t)
Source Edit
proc getSwitch(this: var DaisyField; idx: csize_t): ptr Switch {. importcpp: "#.GetSwitch(#)", ...raises: [], tags: [], forbids: [].}: Get pointer to switch object

Parameters:

idx - Switch index (0-1)

Returns: Pointer to Switch object for direct access

Use case: Access switch methods like pressed(), timeHeldMs(), etc.
Source Edit
proc init(this: var DaisyField; boost: bool = false) {.importcpp: "#.Init(#)", ...raises: [], tags: [], forbids: [].}: Initialize the Daisy Field board

Configures all hardware peripherals:

Audio codec (AK4556, 24-bit/48kHz)

ADC for knobs and CV inputs (with multiplexing)

Keyboard shift registers

OLED display

LED drivers (2× PCA9685, 26 LEDs total)

Gate I/O

MIDI UART

DAC for CV outputs

Parameters:

boost - Enable CPU boost mode (480MHz, default is 400MHz)

Note: Audio and ADC must be started separately with startAudio() and startAdc().
Source Edit
proc keyboardFallingEdge(this: DaisyField; idx: csize_t): bool {. importcpp: "#.KeyboardFallingEdge(#)", ...raises: [], tags: [], forbids: [].}: Detect key release (falling edge)

Parameters:

idx - Key index (0-15)

Returns: true if key was just released (since last call)

Use case: Trigger note-off, stop sequences, etc.
Source Edit
proc keyboardRisingEdge(this: DaisyField; idx: csize_t): bool {. importcpp: "#.KeyboardRisingEdge(#)", ...raises: [], tags: [], forbids: [].}: Detect key press (rising edge)

Parameters:

idx - Key index (0-15)

Returns: true if key was just pressed (since last call)

Use case: Trigger note-on, start sequences, etc.

Example:

for key in 0..<16: if field.keyboardRisingEdge(key): # Key just pressed - play note
Source Edit
proc keyboardState(this: DaisyField; idx: csize_t): bool {. importcpp: "#.KeyboardState(#)", ...raises: [], tags: [], forbids: [].}: Get current state of keyboard key

Parameters:

idx - Key index (0-15)
0-7: Row B (bottom row, left to right)

8-15: Row A (top row, left to right)

Returns: true if key is currently pressed

Note: Call processDigitalControls() first to update state.
Source Edit
proc processAllControls(this: var DaisyField) {. importcpp: "#.ProcessAllControls()", ...raises: [], tags: [], forbids: [].}: Update all control inputs (analog + digital)

Convenience method. Equivalent to:

field.processAnalogControls() field.processDigitalControls()
Source Edit
proc processAnalogControls(this: var DaisyField) {. importcpp: "#.ProcessAnalogControls()", ...raises: [], tags: [], forbids: [].}: Update analog control values (knobs and CV inputs)

Call regularly in main loop (e.g., every 1-10ms). Handles multiplexer switching and ADC filtering.
Source Edit
proc processDigitalControls(this: var DaisyField) {. importcpp: "#.ProcessDigitalControls()", ...raises: [], tags: [], forbids: [].}: Update digital control states (keyboard, switches, gate inputs)

Call regularly in main loop (e.g., every 1ms). Reads shift registers for keyboard scanning.
Source Edit
proc setAudioBlockSize(this: var DaisyField; size: csize_t) {. importcpp: "#.SetAudioBlockSize(#)", ...raises: [], tags: [], forbids: [].}: Set audio block size (must be called before startAudio) Source Edit
proc setAudioSampleRate(this: var DaisyField; samplerate: SampleRate) {. importcpp: "#.SetAudioSampleRate(#)", ...raises: [], tags: [], forbids: [].}: Set audio sample rate (must be called before startAudio) Source Edit
proc setCvOut1(this: var DaisyField; val: uint16) {.importcpp: "#.SetCvOut1(#)", ...raises: [], tags: [], forbids: [].}: Set CV output 1 value

Parameters:

val - 12-bit value (0-4095) corresponding to 0-5V

Voltage mapping: voltage = val * 5.0 / 4095.0

Example:

field.setCvOut1(2048) # Output 2.5V field.setCvOut1(4095) # Output 5.0V
Source Edit
proc setCvOut2(this: var DaisyField; val: uint16) {.importcpp: "#.SetCvOut2(#)", ...raises: [], tags: [], forbids: [].}: Set CV output 2 value

Parameters:

val - 12-bit value (0-4095) corresponding to 0-5V

Source Edit
proc startAdc(this: var DaisyField) {.importcpp: "#.StartAdc()", ...raises: [], tags: [], forbids: [].}: Start ADC for analog controls (knobs and CV inputs)

Uses CD4051 multiplexer for 8 knobs + 4 CV inputs. Must be called before reading knob/CV values.
Source Edit
proc startAudio(field: var DaisyField; callback: AudioCallback) {....raises: [], tags: [], forbids: [].}: Start audio processing with multi-channel (non-interleaved) callback

Example:

proc audioCallback(input, output: AudioBuffer, size: int) {.cdecl.} = for i in 0..<size: output[0][i] = input[0][i] * 0.5 output[1][i] = input[1][i] * 0.5
Source Edit
proc startAudio(field: var DaisyField; callback: InterleavingAudioCallback) {. ...raises: [], tags: [], forbids: [].}: Start audio processing with interleaved callback

Example:

proc audioCallback(input, output: InterleavedAudioBuffer, size: int) {.cdecl.} = for i in 0..<size: output[i * 2] = input[i * 2] * 0.5 output[i * 2 + 1] = input[i * 2 + 1] * 0.5
Source Edit
proc stopAdc(this: var DaisyField) {.importcpp: "#.StopAdc()", ...raises: [], tags: [], forbids: [].}: Stop ADC conversion Source Edit
proc stopAudio(field: var DaisyField) {.importcpp: "#.StopAudio()", ...raises: [], tags: [], forbids: [].}: Stop audio processing Source Edit
proc vegasMode(this: var DaisyField) {.importcpp: "#.VegasMode()", ...raises: [], tags: [], forbids: [].}: LED test pattern / light show

Cycles through all 26 LEDs and updates OLED display. Blocking function - runs until interrupted.

Use case: Hardware testing, visual demo
Source Edit

Exports

initOledSpi, drawPixel, initOledI2c, height, width, SSD130x4WireSpiTransportConfig, fill, OledDisplay, OledDisplay128x32I2c, fillRect, OledDisplay128x64Spi, OledDisplay128x32Spi, OledDisplay64x32Spi, Defaults, drawCircle, SSD130xSpiPinConfig, drawLine, OLED_I2C_ADDRESS_DEFAULT, OledDisplayI2cConfig, OLED_I2C_ADDRESS_ALT, update, OledDisplay64x32I2c, OledDisplaySpiConfig, OledDisplay64x48Spi, OledDisplay64x48I2c, drawRect, SSD130xI2CTransportConfig, OledDisplay128x64I2c, Defaults, setAllToRaw, clearAllLeds, init, continueTransmission, PCA9685_PRESCALE, getDriverForLed, initializeDrivers, initializeBuffers, PCA9685_I2C_BASE_ADDRESS, setAllTo, getNumLeds, PCA9685_MODE2, delayMs, setLedRaw, setLed, getDriverChannelForLed, setLed, swapBuffersAndTransmit, LedDriverPca9685, GAMMA_TABLE, PCA9685_LED0, delayTicks, Pca9685TransmitBuffer, LedDriverConfig, LedDriverDmaBuffer, setAllTo, delayUs, setLed, swapBuffersAndTransmit, FieldLedDriver, getStartCycleForLed, PCA9685_MODE1, trig, init, state, GateIn